1976 – Polish mathematical physicist Roman Stanisław Ingarden publishes a seminal paper entitled "Quantum Information Theory" in Reports on Mathematical Physics, vol. 10, 43–72, 1976. (The paper was submitted in 1975.) It is one of the first attempts at creating a quantum information theory, showing that Shannon information theory cannot directly be generalized to the quantum case, but rather that it is possible to construct a quantum information theory, which is a generalization of Shannon's theory, within the formalism of a generalized quantum mechanics of open systems and a generalized concept of observables (the so-called semi-observables).

Peter Shor, at AT&T's Bell Labs in New Jersey, discovers an important algorithm. It allowed a quantum computer to factor large integers quickly. It solved both the factoring problem and the discrete log problem. Shor's algorithm could theoretically break many of the cryptosystems in use today. Its invention sparked a tremendous interest in quantum computers.

Lov Grover, at Bell Labs, invented the quantum database search algorithm. The quadratic speedup is not as dramatic as the speedup for factoring, discrete logs, or physics simulations. However, the algorithm can be applied to a much wider variety of problems. Any problem that had to be solved by random, brute-force search, could now have a quadratic speedup.

1999 – Samuel L. Braunstein and collaborators showed that there was no mixed state quantum entanglement in any bulk NMR experiment. Pure state quantum entanglement is necessary for any quantum computational speedup, and thus this gave evidence that NMR computers would not yield benefit over classical computer. It was still an open question as to whether mixed state entanglement is necessary for quantum computational speedup[10]

Noah Linden and Sandu Popescu proved that the presence of entanglement is a necessary condition for a large class of quantum protocols. This, coupled with Brauenstein's result (see 1999 above), called the validity of NMR quantum computation into question.[11]

Emanuel Knill, Raymond Laflamme, and Gerard Milburn show that optical quantum computing is possible with single photon sources, linear optical elements, and single photon detectors, launching the field of linear optical quantum computing.

2002 – The Quantum Information Science and Technology Roadmapping Project, involving some of the main participants in the field, laid out the Quantum computation roadmap.

Two teams of physicists have measured the capacitance of a Josephson junction for the first time. The methods could be used to measure the state of quantum bits in a quantum computer without disturbing the state.[14]

In December, the first quantum byte, or qubyte, is announced to have been created by scientists at The Institute of Quantum Optics and Quantum Information at the University of Innsbruck in Austria, with the formal paper published in the December 1 issue of Nature.

Researchers from the University of Illinois at Urbana-Champaign use the Zeno Effect, repeatedly measuring the properties of a photon to gradually change it without actually allowing the photon to reach the program, to search a database without actually "running" the quantum computer.[16]

Vlatko Vedral of the University of Leeds and colleagues at the universities of Porto and Vienna found that the photons in ordinary laser light can be quantum mechanically entangled with the vibrations of a macroscopic mirror.[17]